Speed and call quality testMy IP addressIP subnet calculatorDNS reportWhoIs lookupRemote support

Internet and network

Speed and call quality testTest delay, jitter and speed, with a focus on phone calls.My IP addressYour public IPv4 and IPv6 addresses, provider and address range.WhoIs lookupWho owns a domain or IP address, when it expires, and its DNS.DNS reportEvery DNS record for a domain, with email setup checked.IP subnet calculatorWork out a network's range, mask and hosts, and split it into subnets.

Computers and devices

Update checkIs this computer, phone and browser up to date? With links to update.Camera and mic testCheck your webcam and microphone before a call.Test print pagePrint an A4 page to check a printer: edges, text, line art and colours.

Make and print

Clean textStrip hidden characters, smart quotes and odd spaces from pasted text.QR code makerMake a QR code for a link, contact or message. Nothing leaves your browser.Wi-Fi QR posterPrint an A4 poster that lets guests join your Wi-Fi by scanning.

Surftec support

Remote supportLet a Surftec engineer connect to your computer to help you.All workingA full-screen confirmation that everything is up and running.

Surftec

Surftec websiteServices, news and how to contact Surftec
Cloud Tools
Guest
GuestNot signed in

Surftec customers will be recognised automatically when they use these tools from their office network.

Customer sign-in is coming soon.

IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network26.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
26.0.0.0
Broadcast address
26.255.255.255
First usable
26.0.0.1
Last usable
26.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 1A000000 · Integer 436207616 to 452984831
Reverse DNS zone
26.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011010..00000000.00000000.0000000026.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00011010..00000000.00000000.0000000026.0.0.0
Broadcast00011010..11111111.11111111.1111111126.255.255.255
Split into smaller subnets/18
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

26.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
126.0.0.0/1826.0.0.1 to 26.0.63.25426.0.63.25516,382
226.0.64.0/1826.0.64.1 to 26.0.127.25426.0.127.25516,382
326.0.128.0/1826.0.128.1 to 26.0.191.25426.0.191.25516,382
426.0.192.0/1826.0.192.1 to 26.0.255.25426.0.255.25516,382
526.1.0.0/1826.1.0.1 to 26.1.63.25426.1.63.25516,382
626.1.64.0/1826.1.64.1 to 26.1.127.25426.1.127.25516,382
726.1.128.0/1826.1.128.1 to 26.1.191.25426.1.191.25516,382
826.1.192.0/1826.1.192.1 to 26.1.255.25426.1.255.25516,382
926.2.0.0/1826.2.0.1 to 26.2.63.25426.2.63.25516,382
1026.2.64.0/1826.2.64.1 to 26.2.127.25426.2.127.25516,382
1126.2.128.0/1826.2.128.1 to 26.2.191.25426.2.191.25516,382
1226.2.192.0/1826.2.192.1 to 26.2.255.25426.2.255.25516,382
1326.3.0.0/1826.3.0.1 to 26.3.63.25426.3.63.25516,382
1426.3.64.0/1826.3.64.1 to 26.3.127.25426.3.127.25516,382
1526.3.128.0/1826.3.128.1 to 26.3.191.25426.3.191.25516,382
1626.3.192.0/1826.3.192.1 to 26.3.255.25426.3.255.25516,382
1726.4.0.0/1826.4.0.1 to 26.4.63.25426.4.63.25516,382
1826.4.64.0/1826.4.64.1 to 26.4.127.25426.4.127.25516,382
1926.4.128.0/1826.4.128.1 to 26.4.191.25426.4.191.25516,382
2026.4.192.0/1826.4.192.1 to 26.4.255.25426.4.255.25516,382
2126.5.0.0/1826.5.0.1 to 26.5.63.25426.5.63.25516,382
2226.5.64.0/1826.5.64.1 to 26.5.127.25426.5.127.25516,382
2326.5.128.0/1826.5.128.1 to 26.5.191.25426.5.191.25516,382
2426.5.192.0/1826.5.192.1 to 26.5.255.25426.5.255.25516,382
2526.6.0.0/1826.6.0.1 to 26.6.63.25426.6.63.25516,382
2626.6.64.0/1826.6.64.1 to 26.6.127.25426.6.127.25516,382
2726.6.128.0/1826.6.128.1 to 26.6.191.25426.6.191.25516,382
2826.6.192.0/1826.6.192.1 to 26.6.255.25426.6.255.25516,382
2926.7.0.0/1826.7.0.1 to 26.7.63.25426.7.63.25516,382
3026.7.64.0/1826.7.64.1 to 26.7.127.25426.7.127.25516,382
3126.7.128.0/1826.7.128.1 to 26.7.191.25426.7.191.25516,382
3226.7.192.0/1826.7.192.1 to 26.7.255.25426.7.255.25516,382
3326.8.0.0/1826.8.0.1 to 26.8.63.25426.8.63.25516,382
3426.8.64.0/1826.8.64.1 to 26.8.127.25426.8.127.25516,382
3526.8.128.0/1826.8.128.1 to 26.8.191.25426.8.191.25516,382
3626.8.192.0/1826.8.192.1 to 26.8.255.25426.8.255.25516,382
3726.9.0.0/1826.9.0.1 to 26.9.63.25426.9.63.25516,382
3826.9.64.0/1826.9.64.1 to 26.9.127.25426.9.127.25516,382
3926.9.128.0/1826.9.128.1 to 26.9.191.25426.9.191.25516,382
4026.9.192.0/1826.9.192.1 to 26.9.255.25426.9.255.25516,382
4126.10.0.0/1826.10.0.1 to 26.10.63.25426.10.63.25516,382
4226.10.64.0/1826.10.64.1 to 26.10.127.25426.10.127.25516,382
4326.10.128.0/1826.10.128.1 to 26.10.191.25426.10.191.25516,382
4426.10.192.0/1826.10.192.1 to 26.10.255.25426.10.255.25516,382
4526.11.0.0/1826.11.0.1 to 26.11.63.25426.11.63.25516,382
4626.11.64.0/1826.11.64.1 to 26.11.127.25426.11.127.25516,382
4726.11.128.0/1826.11.128.1 to 26.11.191.25426.11.191.25516,382
4826.11.192.0/1826.11.192.1 to 26.11.255.25426.11.255.25516,382
4926.12.0.0/1826.12.0.1 to 26.12.63.25426.12.63.25516,382
5026.12.64.0/1826.12.64.1 to 26.12.127.25426.12.127.25516,382
5126.12.128.0/1826.12.128.1 to 26.12.191.25426.12.191.25516,382
5226.12.192.0/1826.12.192.1 to 26.12.255.25426.12.255.25516,382
5326.13.0.0/1826.13.0.1 to 26.13.63.25426.13.63.25516,382
5426.13.64.0/1826.13.64.1 to 26.13.127.25426.13.127.25516,382
5526.13.128.0/1826.13.128.1 to 26.13.191.25426.13.191.25516,382
5626.13.192.0/1826.13.192.1 to 26.13.255.25426.13.255.25516,382
5726.14.0.0/1826.14.0.1 to 26.14.63.25426.14.63.25516,382
5826.14.64.0/1826.14.64.1 to 26.14.127.25426.14.127.25516,382
5926.14.128.0/1826.14.128.1 to 26.14.191.25426.14.191.25516,382
6026.14.192.0/1826.14.192.1 to 26.14.255.25426.14.255.25516,382
6126.15.0.0/1826.15.0.1 to 26.15.63.25426.15.63.25516,382
6226.15.64.0/1826.15.64.1 to 26.15.127.25426.15.127.25516,382
6326.15.128.0/1826.15.128.1 to 26.15.191.25426.15.191.25516,382
6426.15.192.0/1826.15.192.1 to 26.15.255.25426.15.255.25516,382
6526.16.0.0/1826.16.0.1 to 26.16.63.25426.16.63.25516,382
6626.16.64.0/1826.16.64.1 to 26.16.127.25426.16.127.25516,382
6726.16.128.0/1826.16.128.1 to 26.16.191.25426.16.191.25516,382
6826.16.192.0/1826.16.192.1 to 26.16.255.25426.16.255.25516,382
6926.17.0.0/1826.17.0.1 to 26.17.63.25426.17.63.25516,382
7026.17.64.0/1826.17.64.1 to 26.17.127.25426.17.127.25516,382
7126.17.128.0/1826.17.128.1 to 26.17.191.25426.17.191.25516,382
7226.17.192.0/1826.17.192.1 to 26.17.255.25426.17.255.25516,382
7326.18.0.0/1826.18.0.1 to 26.18.63.25426.18.63.25516,382
7426.18.64.0/1826.18.64.1 to 26.18.127.25426.18.127.25516,382
7526.18.128.0/1826.18.128.1 to 26.18.191.25426.18.191.25516,382
7626.18.192.0/1826.18.192.1 to 26.18.255.25426.18.255.25516,382
7726.19.0.0/1826.19.0.1 to 26.19.63.25426.19.63.25516,382
7826.19.64.0/1826.19.64.1 to 26.19.127.25426.19.127.25516,382
7926.19.128.0/1826.19.128.1 to 26.19.191.25426.19.191.25516,382
8026.19.192.0/1826.19.192.1 to 26.19.255.25426.19.255.25516,382
8126.20.0.0/1826.20.0.1 to 26.20.63.25426.20.63.25516,382
8226.20.64.0/1826.20.64.1 to 26.20.127.25426.20.127.25516,382
8326.20.128.0/1826.20.128.1 to 26.20.191.25426.20.191.25516,382
8426.20.192.0/1826.20.192.1 to 26.20.255.25426.20.255.25516,382
8526.21.0.0/1826.21.0.1 to 26.21.63.25426.21.63.25516,382
8626.21.64.0/1826.21.64.1 to 26.21.127.25426.21.127.25516,382
8726.21.128.0/1826.21.128.1 to 26.21.191.25426.21.191.25516,382
8826.21.192.0/1826.21.192.1 to 26.21.255.25426.21.255.25516,382
8926.22.0.0/1826.22.0.1 to 26.22.63.25426.22.63.25516,382
9026.22.64.0/1826.22.64.1 to 26.22.127.25426.22.127.25516,382
9126.22.128.0/1826.22.128.1 to 26.22.191.25426.22.191.25516,382
9226.22.192.0/1826.22.192.1 to 26.22.255.25426.22.255.25516,382
9326.23.0.0/1826.23.0.1 to 26.23.63.25426.23.63.25516,382
9426.23.64.0/1826.23.64.1 to 26.23.127.25426.23.127.25516,382
9526.23.128.0/1826.23.128.1 to 26.23.191.25426.23.191.25516,382
9626.23.192.0/1826.23.192.1 to 26.23.255.25426.23.255.25516,382
9726.24.0.0/1826.24.0.1 to 26.24.63.25426.24.63.25516,382
9826.24.64.0/1826.24.64.1 to 26.24.127.25426.24.127.25516,382
9926.24.128.0/1826.24.128.1 to 26.24.191.25426.24.191.25516,382
10026.24.192.0/1826.24.192.1 to 26.24.255.25426.24.255.25516,382
10126.25.0.0/1826.25.0.1 to 26.25.63.25426.25.63.25516,382
10226.25.64.0/1826.25.64.1 to 26.25.127.25426.25.127.25516,382
10326.25.128.0/1826.25.128.1 to 26.25.191.25426.25.191.25516,382
10426.25.192.0/1826.25.192.1 to 26.25.255.25426.25.255.25516,382
10526.26.0.0/1826.26.0.1 to 26.26.63.25426.26.63.25516,382
10626.26.64.0/1826.26.64.1 to 26.26.127.25426.26.127.25516,382
10726.26.128.0/1826.26.128.1 to 26.26.191.25426.26.191.25516,382
10826.26.192.0/1826.26.192.1 to 26.26.255.25426.26.255.25516,382
10926.27.0.0/1826.27.0.1 to 26.27.63.25426.27.63.25516,382
11026.27.64.0/1826.27.64.1 to 26.27.127.25426.27.127.25516,382
11126.27.128.0/1826.27.128.1 to 26.27.191.25426.27.191.25516,382
11226.27.192.0/1826.27.192.1 to 26.27.255.25426.27.255.25516,382
11326.28.0.0/1826.28.0.1 to 26.28.63.25426.28.63.25516,382
11426.28.64.0/1826.28.64.1 to 26.28.127.25426.28.127.25516,382
11526.28.128.0/1826.28.128.1 to 26.28.191.25426.28.191.25516,382
11626.28.192.0/1826.28.192.1 to 26.28.255.25426.28.255.25516,382
11726.29.0.0/1826.29.0.1 to 26.29.63.25426.29.63.25516,382
11826.29.64.0/1826.29.64.1 to 26.29.127.25426.29.127.25516,382
11926.29.128.0/1826.29.128.1 to 26.29.191.25426.29.191.25516,382
12026.29.192.0/1826.29.192.1 to 26.29.255.25426.29.255.25516,382
12126.30.0.0/1826.30.0.1 to 26.30.63.25426.30.63.25516,382
12226.30.64.0/1826.30.64.1 to 26.30.127.25426.30.127.25516,382
12326.30.128.0/1826.30.128.1 to 26.30.191.25426.30.191.25516,382
12426.30.192.0/1826.30.192.1 to 26.30.255.25426.30.255.25516,382
12526.31.0.0/1826.31.0.1 to 26.31.63.25426.31.63.25516,382
12626.31.64.0/1826.31.64.1 to 26.31.127.25426.31.127.25516,382
12726.31.128.0/1826.31.128.1 to 26.31.191.25426.31.191.25516,382
12826.31.192.0/1826.31.192.1 to 26.31.255.25426.31.255.25516,382
12926.32.0.0/1826.32.0.1 to 26.32.63.25426.32.63.25516,382
13026.32.64.0/1826.32.64.1 to 26.32.127.25426.32.127.25516,382
13126.32.128.0/1826.32.128.1 to 26.32.191.25426.32.191.25516,382
13226.32.192.0/1826.32.192.1 to 26.32.255.25426.32.255.25516,382
13326.33.0.0/1826.33.0.1 to 26.33.63.25426.33.63.25516,382
13426.33.64.0/1826.33.64.1 to 26.33.127.25426.33.127.25516,382
13526.33.128.0/1826.33.128.1 to 26.33.191.25426.33.191.25516,382
13626.33.192.0/1826.33.192.1 to 26.33.255.25426.33.255.25516,382
13726.34.0.0/1826.34.0.1 to 26.34.63.25426.34.63.25516,382
13826.34.64.0/1826.34.64.1 to 26.34.127.25426.34.127.25516,382
13926.34.128.0/1826.34.128.1 to 26.34.191.25426.34.191.25516,382
14026.34.192.0/1826.34.192.1 to 26.34.255.25426.34.255.25516,382
14126.35.0.0/1826.35.0.1 to 26.35.63.25426.35.63.25516,382
14226.35.64.0/1826.35.64.1 to 26.35.127.25426.35.127.25516,382
14326.35.128.0/1826.35.128.1 to 26.35.191.25426.35.191.25516,382
14426.35.192.0/1826.35.192.1 to 26.35.255.25426.35.255.25516,382
14526.36.0.0/1826.36.0.1 to 26.36.63.25426.36.63.25516,382
14626.36.64.0/1826.36.64.1 to 26.36.127.25426.36.127.25516,382
14726.36.128.0/1826.36.128.1 to 26.36.191.25426.36.191.25516,382
14826.36.192.0/1826.36.192.1 to 26.36.255.25426.36.255.25516,382
14926.37.0.0/1826.37.0.1 to 26.37.63.25426.37.63.25516,382
15026.37.64.0/1826.37.64.1 to 26.37.127.25426.37.127.25516,382
15126.37.128.0/1826.37.128.1 to 26.37.191.25426.37.191.25516,382
15226.37.192.0/1826.37.192.1 to 26.37.255.25426.37.255.25516,382
15326.38.0.0/1826.38.0.1 to 26.38.63.25426.38.63.25516,382
15426.38.64.0/1826.38.64.1 to 26.38.127.25426.38.127.25516,382
15526.38.128.0/1826.38.128.1 to 26.38.191.25426.38.191.25516,382
15626.38.192.0/1826.38.192.1 to 26.38.255.25426.38.255.25516,382
15726.39.0.0/1826.39.0.1 to 26.39.63.25426.39.63.25516,382
15826.39.64.0/1826.39.64.1 to 26.39.127.25426.39.127.25516,382
15926.39.128.0/1826.39.128.1 to 26.39.191.25426.39.191.25516,382
16026.39.192.0/1826.39.192.1 to 26.39.255.25426.39.255.25516,382
16126.40.0.0/1826.40.0.1 to 26.40.63.25426.40.63.25516,382
16226.40.64.0/1826.40.64.1 to 26.40.127.25426.40.127.25516,382
16326.40.128.0/1826.40.128.1 to 26.40.191.25426.40.191.25516,382
16426.40.192.0/1826.40.192.1 to 26.40.255.25426.40.255.25516,382
16526.41.0.0/1826.41.0.1 to 26.41.63.25426.41.63.25516,382
16626.41.64.0/1826.41.64.1 to 26.41.127.25426.41.127.25516,382
16726.41.128.0/1826.41.128.1 to 26.41.191.25426.41.191.25516,382
16826.41.192.0/1826.41.192.1 to 26.41.255.25426.41.255.25516,382
16926.42.0.0/1826.42.0.1 to 26.42.63.25426.42.63.25516,382
17026.42.64.0/1826.42.64.1 to 26.42.127.25426.42.127.25516,382
17126.42.128.0/1826.42.128.1 to 26.42.191.25426.42.191.25516,382
17226.42.192.0/1826.42.192.1 to 26.42.255.25426.42.255.25516,382
17326.43.0.0/1826.43.0.1 to 26.43.63.25426.43.63.25516,382
17426.43.64.0/1826.43.64.1 to 26.43.127.25426.43.127.25516,382
17526.43.128.0/1826.43.128.1 to 26.43.191.25426.43.191.25516,382
17626.43.192.0/1826.43.192.1 to 26.43.255.25426.43.255.25516,382
17726.44.0.0/1826.44.0.1 to 26.44.63.25426.44.63.25516,382
17826.44.64.0/1826.44.64.1 to 26.44.127.25426.44.127.25516,382
17926.44.128.0/1826.44.128.1 to 26.44.191.25426.44.191.25516,382
18026.44.192.0/1826.44.192.1 to 26.44.255.25426.44.255.25516,382
18126.45.0.0/1826.45.0.1 to 26.45.63.25426.45.63.25516,382
18226.45.64.0/1826.45.64.1 to 26.45.127.25426.45.127.25516,382
18326.45.128.0/1826.45.128.1 to 26.45.191.25426.45.191.25516,382
18426.45.192.0/1826.45.192.1 to 26.45.255.25426.45.255.25516,382
18526.46.0.0/1826.46.0.1 to 26.46.63.25426.46.63.25516,382
18626.46.64.0/1826.46.64.1 to 26.46.127.25426.46.127.25516,382
18726.46.128.0/1826.46.128.1 to 26.46.191.25426.46.191.25516,382
18826.46.192.0/1826.46.192.1 to 26.46.255.25426.46.255.25516,382
18926.47.0.0/1826.47.0.1 to 26.47.63.25426.47.63.25516,382
19026.47.64.0/1826.47.64.1 to 26.47.127.25426.47.127.25516,382
19126.47.128.0/1826.47.128.1 to 26.47.191.25426.47.191.25516,382
19226.47.192.0/1826.47.192.1 to 26.47.255.25426.47.255.25516,382
19326.48.0.0/1826.48.0.1 to 26.48.63.25426.48.63.25516,382
19426.48.64.0/1826.48.64.1 to 26.48.127.25426.48.127.25516,382
19526.48.128.0/1826.48.128.1 to 26.48.191.25426.48.191.25516,382
19626.48.192.0/1826.48.192.1 to 26.48.255.25426.48.255.25516,382
19726.49.0.0/1826.49.0.1 to 26.49.63.25426.49.63.25516,382
19826.49.64.0/1826.49.64.1 to 26.49.127.25426.49.127.25516,382
19926.49.128.0/1826.49.128.1 to 26.49.191.25426.49.191.25516,382
20026.49.192.0/1826.49.192.1 to 26.49.255.25426.49.255.25516,382
20126.50.0.0/1826.50.0.1 to 26.50.63.25426.50.63.25516,382
20226.50.64.0/1826.50.64.1 to 26.50.127.25426.50.127.25516,382
20326.50.128.0/1826.50.128.1 to 26.50.191.25426.50.191.25516,382
20426.50.192.0/1826.50.192.1 to 26.50.255.25426.50.255.25516,382
20526.51.0.0/1826.51.0.1 to 26.51.63.25426.51.63.25516,382
20626.51.64.0/1826.51.64.1 to 26.51.127.25426.51.127.25516,382
20726.51.128.0/1826.51.128.1 to 26.51.191.25426.51.191.25516,382
20826.51.192.0/1826.51.192.1 to 26.51.255.25426.51.255.25516,382
20926.52.0.0/1826.52.0.1 to 26.52.63.25426.52.63.25516,382
21026.52.64.0/1826.52.64.1 to 26.52.127.25426.52.127.25516,382
21126.52.128.0/1826.52.128.1 to 26.52.191.25426.52.191.25516,382
21226.52.192.0/1826.52.192.1 to 26.52.255.25426.52.255.25516,382
21326.53.0.0/1826.53.0.1 to 26.53.63.25426.53.63.25516,382
21426.53.64.0/1826.53.64.1 to 26.53.127.25426.53.127.25516,382
21526.53.128.0/1826.53.128.1 to 26.53.191.25426.53.191.25516,382
21626.53.192.0/1826.53.192.1 to 26.53.255.25426.53.255.25516,382
21726.54.0.0/1826.54.0.1 to 26.54.63.25426.54.63.25516,382
21826.54.64.0/1826.54.64.1 to 26.54.127.25426.54.127.25516,382
21926.54.128.0/1826.54.128.1 to 26.54.191.25426.54.191.25516,382
22026.54.192.0/1826.54.192.1 to 26.54.255.25426.54.255.25516,382
22126.55.0.0/1826.55.0.1 to 26.55.63.25426.55.63.25516,382
22226.55.64.0/1826.55.64.1 to 26.55.127.25426.55.127.25516,382
22326.55.128.0/1826.55.128.1 to 26.55.191.25426.55.191.25516,382
22426.55.192.0/1826.55.192.1 to 26.55.255.25426.55.255.25516,382
22526.56.0.0/1826.56.0.1 to 26.56.63.25426.56.63.25516,382
22626.56.64.0/1826.56.64.1 to 26.56.127.25426.56.127.25516,382
22726.56.128.0/1826.56.128.1 to 26.56.191.25426.56.191.25516,382
22826.56.192.0/1826.56.192.1 to 26.56.255.25426.56.255.25516,382
22926.57.0.0/1826.57.0.1 to 26.57.63.25426.57.63.25516,382
23026.57.64.0/1826.57.64.1 to 26.57.127.25426.57.127.25516,382
23126.57.128.0/1826.57.128.1 to 26.57.191.25426.57.191.25516,382
23226.57.192.0/1826.57.192.1 to 26.57.255.25426.57.255.25516,382
23326.58.0.0/1826.58.0.1 to 26.58.63.25426.58.63.25516,382
23426.58.64.0/1826.58.64.1 to 26.58.127.25426.58.127.25516,382
23526.58.128.0/1826.58.128.1 to 26.58.191.25426.58.191.25516,382
23626.58.192.0/1826.58.192.1 to 26.58.255.25426.58.255.25516,382
23726.59.0.0/1826.59.0.1 to 26.59.63.25426.59.63.25516,382
23826.59.64.0/1826.59.64.1 to 26.59.127.25426.59.127.25516,382
23926.59.128.0/1826.59.128.1 to 26.59.191.25426.59.191.25516,382
24026.59.192.0/1826.59.192.1 to 26.59.255.25426.59.255.25516,382
24126.60.0.0/1826.60.0.1 to 26.60.63.25426.60.63.25516,382
24226.60.64.0/1826.60.64.1 to 26.60.127.25426.60.127.25516,382
24326.60.128.0/1826.60.128.1 to 26.60.191.25426.60.191.25516,382
24426.60.192.0/1826.60.192.1 to 26.60.255.25426.60.255.25516,382
24526.61.0.0/1826.61.0.1 to 26.61.63.25426.61.63.25516,382
24626.61.64.0/1826.61.64.1 to 26.61.127.25426.61.127.25516,382
24726.61.128.0/1826.61.128.1 to 26.61.191.25426.61.191.25516,382
24826.61.192.0/1826.61.192.1 to 26.61.255.25426.61.255.25516,382
24926.62.0.0/1826.62.0.1 to 26.62.63.25426.62.63.25516,382
25026.62.64.0/1826.62.64.1 to 26.62.127.25426.62.127.25516,382
25126.62.128.0/1826.62.128.1 to 26.62.191.25426.62.191.25516,382
25226.62.192.0/1826.62.192.1 to 26.62.255.25426.62.255.25516,382
25326.63.0.0/1826.63.0.1 to 26.63.63.25426.63.63.25516,382
25426.63.64.0/1826.63.64.1 to 26.63.127.25426.63.127.25516,382
25526.63.128.0/1826.63.128.1 to 26.63.191.25426.63.191.25516,382
25626.63.192.0/1826.63.192.1 to 26.63.255.25426.63.255.25516,382

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.